GF-666 restoration help needed.

[lazydays]

Hi guys,

I got a Sharp GF-666 that I would like to refurbish for the summer but I don't really know where to start. I've opened it up and got quite scared of the sheer number of mechanical parts.
I do know electronics, but nothing about vintage audio gear.
I can't find any guides or repair logs for the gf-666 so hopefully you guys can steer me in the right direction

There are a few things I'm wondering about:

- I've found one seller on ebay that sells a belt kit with a lubricant for €35. Is this a steep price for a kit of five belts and lube?

- Are there other special components prone to failure that I can go ahead and order right away?

- One of the speakers suddenly stopped working. I would guess it's simply a matter of a connection issue, but would there be any reason to refurbish the speakers? How would I go about it - is re-foaming enough?

- The metal plate on the left cassette deck is missing. I guess it's impossible to replace it. Are there any makeshift solutions to make it look a bit better?

- One antenna is broken off. Can I just buy a generic replacement?

- There are some scratches in the paint on the top, is the color code for the 666 known?

- Are these units prone to capacitor failure? If so, do anyone have a list of the needed values?

I've probably forgot a lot of stuff, all tips and recommendations are more than welcome.

 

[BoomboxLover48]

Welcome to this beautiful site!

This site is blessed with so many talented and good members.

The speaker failure could be purely because of the need for a complete switch cleaning.

You have to use Deoxit Fader Lube 5 or Deoxit to spray, move it back and forth gently for say 30 times.

There is a rubber sleeve on the capstan will perish after all these years. The type of rubber sharp used on the capstan drive became a sticky mess over a period of time. You might have to find a plastic tube from hobby shops used for fuel lines in small gas engine cars and planes.

I haven't had any cap failure on several GF brands I got. Will it fail? Yes they can. I would say it might fail very rarely.

Antennas are no big deal. You can get the right size from several sellers on EBay or from members here if you are lucky.

The belts can be so much cheaper. One of our members here can direct where to buy them cheap. You didn't mention your location and all the information we have is you use Euro.

You might be able to get a spare metal plate on cassette door or a whole door from our members here if they got one.

I won't worry about cosmetics at this stage. You can always work on it and make it so much better with good looks.

 

[Beosystem10]

Hi, welcome. I've refurbished a few 555s in the last few years as many eBay buyers end up with non-functioning decks in these as a result of sellers not knowing that there's no takeup because they simply run the motors and with no load everything appears to work.

Lube? Dow-Corning HS Silicon grease is used in the areas where metal parts slide along the many standoffs between the three plates that make up the decks, the capstan bushes are porous, absorbent Oillite brand and should be soaked in suitable light gear oil or non-Dexron ATF overnight to revitalise their ability to keep the capstans running without excess resistance. (Picture below, the red thing is a cap from a roll of Kunifer and is just the right size to hold that bushes, one at a time so I have kept the one from the other end too).

Belt kits for these I've had from Revox.de, a German eBay shop specialising in rubbers for cassette (and R2R as the name implies) tape transport mechanism. They were dear but are top quality, Malvern Audio do kits of assorted belts that include enough to replace four from the five (only one counter, hence the odd number) required. Idler tyres are often found melting too, O rings work fine as a substitute and as they're just that - an idler - these are passive relative to speed stability.
The speakers won't need foam jobs as they came with corrugated paper edges where any minor repairs can be made in the usual way with tissue paper and diluted PVA. Car speakers of standard size are a suitable alternative if the o/e ones are dead but it's unlikely and any voice coil rubbing can be addressed with a quick flash from a PP9 radio battery across the coil which shoots it straight 9 times on 10.

The only difference, electronic or mechanical between yours and the 555 is that the 666 has harder heads to allow for playback of metal tapes as well as the other types.

I'll find out the correct bush size if you need to replace those, meanwhile, here's how you prepare them for fitting:

Once you extract the deck plates as a single assembly, dismantling is straightforward enough but it's always good practice to take lots of macro images as you go, even once you've built up dozens of the things. Be careful removing the back cover, there's an aerial connection that uses the foil sandwich construction of that as its screen and it's easily torn during stripdown, which causes excessive 50Hz hum if not repaired prior to reassembly. Many eBay examples have the screen lead dangling and/or the tag sheared from the foil so if yours hums at 50Hz and you can't find a faulty reservoir cap or mains filter, that's why.

 

[lazydays]

Hi guys, thanks for the warm welcome!

I don't know where I got the 666 from, as the unit is a 555.
I've extracted the tape assembly and it now sits here on the work bench looking scary.
I tried both decks and they seem to work fine. I only have some obscure ambient on tape that I can't find on the net so I really can't say if they play as they should.
Without going further inside the only thing I notice is some very small cracks in the two rubber wheels.
Is it worth going the extra bit and replace everything prone to failure any way?

I'm from Sweden, but if anyone have the spare parts I can pay for postage from where ever.

Thanks again!

EDIT: Forgot about the dead speaker. I've tried to clean the L/R switch but the right side is completely silent. All the leds shine constant for the right channel, and moves as usual on the left channel. Any tips on where to go next?

EDIT 2: So it seems three out of four speakers are dead. Is that probable and how would I go about troubleshooting this?

EDIT 3: Even with the speakers disconnected the right row of leds are constantly lit. Tried with headphones and get sound on left channel.

EDIT 4: I've now had the chance to try the unit with line out and line in, bypassing those troublesome faders and the channel is still dead. My guess is that the problem originates in the main pcb. Can my problem be a lost ground signal somewhere, as the indicator leds are constantly on? And how would I go about finding the source of the problem? Thanks in advance!

 

[Beosystem10]

666 was essentially the same set but with heads suitable for metal tape.

These decks can appear scary to someone who's not used with repairing things and for sure they're a little more complex than those in some Sharps however, they're very well built and that build quality makes them easy to dismantle so don't be too concerned, take lots of pictures as you progress and while you're that far along, it's a shame not to replace capstan sleeves, check and clean (with glycerine) idler tyres and pinch roller and replace those while you're in about at it if they're less than perfect.